WO 2006/035034 discloses a group of chromen-2-one derivatives useful as monoamine neurotransmitter re-uptake inhibitors. In this document the (8-H-8-aza-bicyclo[3.2.1]oct-3-yloxy)-chromen-2-one-yl derivatives are synthesized by deprotection of the relevant 8-methyl- or 8-tert-butoxycarbonyl-8-aza-bicyclo[3.2.1]oct-3-yloxy-chromen-2-one derivative.
However, when synthesizing larger amounts of the pharmaceutical compound, the synthesis needs to be scalable, eg. to produce crystalline intermediates and an end product that does not need chromatographic purification.
Further, the process should apply to specific requirements regarding purity and reproducibility.
Therefore, when in connection with the scaling up of this group of compounds a more suitable synthesis was invented.